Method for the production of metallic pre-forms



June 1965 H. FELDMANN ETAL 3,137,421

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June 8, 1965 H. FELDMANN ETAL 3,137,421

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METHOD FOR THE PRODUCTION OF METALLIC FEE-FORMS F'iied Sept. 8. 1961 6 Sheets-Sheet 6 mrslvrak HEINZ FELPHANN v GUILLERUHE HHHHING 37' m n v I M0 I United States Patent METHOD FOR THE PlROliUCTlON F METALLEC PRE-FGRMS Heinz Feldmann, Weingarten, Wurttemberg, Germany,

and Guilleaume Scharning, Le Perreux, France, assignors to International Cold Forging Corporation, Monaco, Monaco Filed Sept. 8, 1961, Ser. No. 136,828 (Claims priority, application Germany, Sept. 8, 1960, J 18,681,J 18,682, J 18,683 3 Claims. (Cl. 29-417) quent cold forming difficult and under certain circumstances may render the finished product useless.

Prior to the present invention, it was necessary to form the cropped cutoffs individually in a totally enclosed pressure tool or press tool which operated to form the cutoffs into accurately defined pre-forrns. This method is very. complicated and requires costly tools which have only a relatively short working life due to the high pressure forces which are involved in accurately forming the blanks. In addition, with the prior art method, the cropped blanks must normally be annealed and surface treated prior to the pre-forming operation, and this greatly increases the cost of the production of such items.

In accordance with the present invention, the produc-..

tion of metallic blanks as pre-forms for cold forging is accomplished by cutting the stock. and thereafter flattening the cut pieces through upsetting. This is followed by removing the irregularity of the surface bymethods such as grinding, scraping or milling. An advantage of the upsetting procedure is that this provides a starting blank with accurately plane-parallel end faces which are made by relatively small power requirements. The preforms produced by the flattening or upsetting and subsequent de-burring of the cropped blanks ensure the produc tion of reliable finished components in the subsequent cold forging operation.

' In accordance with a preferred arrangement, means are provided for croppingor cutting individual blanks and thereafterconyeying them into association with a power press which is employed to flatten the ends thereof. Thereupon, the blanks are conveyed further to a de burring device which advantageously includes a grinding wheel. In one arrangement, the device includes a'reciprocable slide having a cut-off knife which acts -to sever the individual blank pieces. Conveyor means are provided below the plane of cut-off to pick up the severed pieces and to move them beneath a power ram which is released by the upward movement of the slide having the cutting knife. The power ram effects flattening of the blanks which are thereafter conveyed to a device for effecting the de-burring. s

Accordingly, it is an object of this invention to provide an improved method for the production of metallic preforms for cold forging. a

A further object of the invention for the production of metallic pro-forms for cold forging which include s cutting blank pieces from a bar of such material, thereafter upsetting the blank by flattening opposite ends to form parallel surfaces and thereafter finishing the surface of the cut and pressed blanks to remove the burrs therefrom.

is to provide a method s s er Patented June 8, 1965 A further object of the invention is to provide a method for the production of metallic pre-forms for cold forging metals. which is simple in concept and economical to carry out.

The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this specification. For a better understanding of the invention, its operating advantages and specific objects attained by its use, reference should be had to theaccompanying drawings and descriptive matter in which there are illustrated and described preferred embodiments of the invention.

In the drawings:

FIG. l is a transverse cross section of a cropped bar stock cutoff;

FIG. 2 indicates the cutoff in a flattened condition;

FIG. 3 indicates the cutoff in a de-burred condition;

FIG. 4 is a somewhat schematic indication of an apparatus for effecting the cropping, upsetting and deburring of a metallic pre-form for cold forging constructed in accordance with the invention;

FIG. 5 is atransverse section through a de-burring apparatus constructed in accordance with the invention; I FlG. 6 is a top plan view of the apparatus indicated in FIG. 5;

FIG. 7 is a performance curve indicating the force velocity characteristics of the machine in relation to the ram displacement of a press serving for the cropping and upsetting;

FIGS. 8 to 10 are transverse sections of another embodiment having a press ram and indicated with the cropping and upsetting tool in three stages of operation;

FIGS. 11 to 13 are transverse sections taken along the line 11-11 of FIG. 9 of an automatically controllable lock for the ram working stroke; and

FIG. 14 is a somewhat schematic indication of the cropping, conveying and upsetting mechanism with the cropping tool and the ram shown independently for the purpose of clarity.

Referring to the drawings in particular, there is disclosed a method and device for cropping or cutting metallic pro-forms or blanks to be used for cold forging. In the process, a bar stock cutoff or piece 1 is formed by feeding a piece of bar stock 2 between clamping guide members 3, 3 which hold the bar stock while a movable knife blade 4 reciprocates past a stationary knife blade 5 to effect the cropping and to form the cutoff 1. V

In accordance with the invention, a conveyor such as a chain conveyor 6 is trained to run beneath the cutofi knives and includes a vertical portion 6a in a position to pick up each cutoff orpiece las it is severed. The chain conveyor 6 advances the cutoff 1 through a horizontal conveyor portion 6b into association with an upsetting mechanism' generally designated 20 which includes a stationary die 7 and a movable ram or punch 8. In FIG. 4, a portion of the piece 1 is indicated in a flattened condition 1a with the opposite sides made parallel by the operation of the ram 8. The left-hand section of thepiece 1 is indicated in its unflattened or non-upset condition. a

The flattened blank 1a is moved automatically by a conveyor portion 6c into association with a de-burring apparatus, which in the embodiment indicated, is a grinding wheel or milling cutter 9. I

The milling cutter 9 as indicated in detail in FIGS. 5 and 6 includes a grinding wheel 9a which is affixed to a stub shaft 9' which is located in a bushing 9". The lower free end of the stub shaft 9 is driven in the direction indicated by the arrow A by a mechanism (not shown). Directly below the outer periphery of the grinding wheel 9a is a rotating collar 20 which rotates in the opposite direction to the stub shaft 9' as indicated by the arrow B. The collar 24) is positively coupled to the bush 21 which is rotated through a driving gear formed at its lower end which meshes with a reduction gear 22. The bearing bush 9" is an adjustable eccentric bush which in turn is located within a bush 23 which is also arranged as an eccentric collar. Both bushes 9 and 23 are located in the stationary retaining bush 24 and, because of their eccentric arrangement, serve for adjusting the position of the grinding wheel 9a in relation to the bar stock cutoffs 1a.

The bar stock cutoffs 1a are continuously supplied to the de-burring apparatus 9 by the automatic feeder or conveyor 60 and are transferred to a rotating abutment collar 25 and pressed against the friction collar 20 and the effective working surface of the de-burring tool 9a by counter rolls or retaining rolls 10 which are attached to spring loaded swivel arms 42. The rolls 10 are not driven but rotate by frictional contact with the pieces 1a. When the burr is removed from the blank, it obtains the shape as indicated in FIG. 3. This preform indicated in FIG. 3 is then converted into the final finished component by cold forging.

In FIGS. 7 to 14, inclusive, there is indicated another embodiment of the invention with the performance characteristic indicate graphically in FIG. 7. In this embodiment, the cropping and upsetting of the blanks are accomplished in a single cycle or stroke of operation of the machine. In FIG. 7, the characteristics of the normal cuttage during one working stroke, also during the down stroke of the press ram from the top dead center to the bottom dead center, are indicated. Broken line b shows the velocity characteristics of the machine. In accordance with the invention, the bar stock cutoffs are cut off at the beginning of the down stroke of the ram, that is to say, shortly after top dead center. The corresponding working diagram As is indicated by the line 0. The cropped blank is flattened by upsetting shortly before bottom dead center is reached. This working diagram Av is indicated by the line a. The time interval between the two operations, cropping and flattening, is utilized for feeding the bar stock material into the tool.

In FIGS. 8 to 10 there are indicated the design and arrangement of the cropping and upsetting tool in combination with a press ram. The mechanism includes an upper blade portion 4 which is carried by a slide or slide holder 11 which reciprocates with the ram 8 in a guideway 12 of the press. The lower blade of the cropping tool is combined with the press table.

The bar stock 2 is fed to the cropping tool from the side as in the other embodiment. The preforming punch or ram 8 which is provided to flatten the cropped bar stock cutoffs 1a is guided in the cropping blade slide holder 11.

In FIG. 8 there is indicated the cropping and upsetting tool blade 4 in a position just prior to cutting a piece from the bar stock 2. The ram 8 is in the top dead center position. In FIG. 9, the blade 4 is indicated in a position at the completion of the cropping operation At this time, the cropping slide 11 starts to return upwards into the starting position while the punch or ram 8 continues to move downwardly. The cropped bar cutoff 1 drops through a gap 13 and onto a conveyor belt 6 which is disposed so that it picks up the cutoff piece 1 and carries it into an operative poistion beneath the ram 8. This operation takes place shortly before bottom dead center of the ram stroke. The cropped bar cutoff is flattened in this position so that it can be provided with plane-parallel end surfaces as can be seen from FIG. 10, which illustrates the operation. After completion of the upsetting operation, the pre-form punch 8 returns to its starting position (top dead center) so that the next operating cycle can commence as described previously. The bar 2 to be cropped is fed forward for the next cropping operation during the upsetting operation.

As indicated in FIGS. 11 to 13, the preforming punch or ram 8 is controlled by an automatically operating lock mechanism. This consists of two sliding elements 14 and 15 which are supported on block members 44 and 46 which are biased in an upward direction by spring 17. Springs 16 are also provided to urge the Wedge shaped blocks 14 and 15 in directions toward one another. The ram 8 is supported above the wedge members 15 when the slide 11 is in a position at or below that indicated in FIG. 11, i.e., permitting inward movement of the wedge members 14 and 15 toward each other.

After completion of the cropping operation by the cropping blade 4 carried by the slide 11, the slide moves upwardly under the urging of springs to contact the wedge members 14 and 15 and displace them in opposite outward directions. The wedge members 14 and 15 move outwardly sufficiently to release the pre-forming punch or ram 8 which effects the upsetting operation as indicated in FIG. 13.

In FIG. 14, there is indicated schematically the operation of the conveyor 6 which includes outstanding guides or cleats 48 carried by a chain 50 which is arranged to run over a pulley 52. The cleats 48 move into the gap 13 to close it off and support each piece In as it is severed from the bar stock 2 in succession. The arrangement is such that the severed side 1' is always supported in an upward position and moves around on the wheel 52 along the flat conveyor portion 6b into a position beneath the ram member 8 for completion of the upsetting operation. Thus, the pre-forming punch or ram 8 always presses against the uneven cutting surface of the bar stock cutoff.

While specific embodiments of the invention have been shown and described in detail to illustrate the application of the inventive principles, it will be understood that the invention may be embodied otherwise without departing from such principles.

What is claimed is:

1. A method for the production of metallic preforms for cold forging comprising, cutting off pieces from a bar stock to form cropped cutoffs, thereafter flattening the cutoffs by upsetting to form burrs extending outwardly from the flat surface and subsequently machining the burrs to remove the burrs from the upset cutoff pieces.

2. A method according to claim 1, wherein the cropping, upsetting and de-burring operations are effected in a positively controlled sequence.

3. A method for the production of metallic blanks for cold forging comprising, cutting a length of material from a bar stock to form cropped bar stock cutoffs, transporting the cutoffs to an upsetting station, upsetting the cutoffs to form burrs extending outwardly from the upset cutoff, and thereafter removing the burrs from the upset cutoffs.

References Cited by the Examiner UNITED STATES PATENTS 328,436 10/85 Simpson 29-556 2,341,462 2/44 Matson 29-34 2,362,701 11/44 Koehring 29-34 2,813,279 11/57 Friedman 29-556 2,991,552 7/61 Chatfield 29-556 WHITMORE A. WILTZ, Primary Examiner.

RICHARD H. EANES, JR., THOMAS H. EAGER,

Examiners. 

1. A METHOD FOR THE PRODUCTION OF METALLIC PREFORMS FOR COLD FORGING COMPRISING, CUTTING OFF PIECES FROM A BAR STOCK TO FORM CROPPED CUTOFFS, THEREAFTER FLATTENING THE CUTOFFS BY UPSETTING TO FORM BURRS EXTENDING OUTWARDLY FROM THE FLAT SURFACE AND SUBSEQUENTLY MACHINING THE BURRS TO REMOVE THE BURRS FROM THE UPSET CUTOFF PIECES. 